As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
KAUS/KDAY - FLT 107 - AFTER TAKEOFF, NR 4 ENGINE FIRE WARNING SOUNDED. THE CREW DISCHARGED FIRE AGENT AND SHUT DOWN NR 4 ENGINE. N964R RETURNED TO KAUS. MAINTENANCE FOUND WATER IN THE FIRE LOOP ELECTRICAL CONNECTOR. MAINTENANCE DRIED AND RESECURED THE ELECTRICAL CONNECTOR ON THE FIRE LOOP AND CHANGED THE FIRE BOTTLE AND SQUIBS. ALL SYSTEMS OPERATED NORMALLY ON GROUND CHECK.